Ruthenium film forming method and substrate processing system

ABSTRACT

A ruthenium film forming method includes: causing chlorine to be adsorbed to an upper portion of a recess at a higher density than to a lower portion of the recess by supplying a chlorine-containing gas to a substrate including an insulating film and having the recess; and forming a ruthenium film in the recess by supplying a Ru-containing precursor to the recess to which the chlorine is adsorbed.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2019-129545, filed on Jul. 11, 2019, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a ruthenium film forming method and asubstrate processing system.

BACKGROUND

There is known a technique of embedding a ruthenium film in a recesssuch as a trench or the like provided in an insulating layer (see, e.g.,Patent Document 1).

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese laid-open publication No. 2018-14477

SUMMARY

According to an aspect of the present disclosure, there is provided aruthenium film forming method including: causing chlorine to be adsorbedto an upper portion of a recess at a higher density than to a lowerportion of the recess by supplying a chlorine-containing gas to asubstrate including an insulating film and having the recess; andforming a ruthenium film in the recess by supplying a Ru-containingprecursor to the recess to which the chlorine is adsorbed.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentdisclosure, and together with the general description given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present disclosure.

FIGS. 1A to 1F are sectional process views showing an example of aruthenium film forming method according to one embodiment.

FIGS. 2A to 2I are sectional process views showing another example ofthe ruthenium film forming method according to one embodiment.

FIG. 3 is a schematic diagram showing an example of a configuration of asubstrate processing system.

FIG. 4 is a schematic diagram showing an example of a processingapparatus that executes a process of a step of causing chlorine to beadsorbed.

FIG. 5 is a schematic diagram showing an example of a processingapparatus that executes a process of a step of forming a ruthenium film.

FIGS. 6A and 6B are views for explaining an adsorption inhibition effectof chlorine.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. In the followingdetailed description, numerous specific details are set forth in orderto provide a thorough understanding of the present disclosure. However,it will be apparent to one of ordinary skill in the art that the presentdisclosure may be practiced without these specific details. In otherinstances, well-known methods, procedures, systems, and components havenot been described in detail so as not to unnecessarily obscure aspectsof the various embodiments.

Hereinafter, a non-limiting exemplary embodiment of the presentdisclosure will be described with reference to the accompanyingdrawings. Throughout the accompanying drawings, the same orcorresponding members or parts will be denoted by the same orcorresponding reference numerals, and the redundant description thereofwill be omitted.

[Ruthenium Film Forming Method]

An example of a method for forming a ruthenium (Ru) film according toone embodiment will be described. FIGS. 1A to 1F are sectional processviews showing an example of a ruthenium film forming method according toone embodiment.

The ruthenium film forming method shown in FIGS. 1A to 1F includes astep of causing chlorine to be adsorbed to an upper portion of a recessat a higher density than to a lower portion of the recess by supplying achlorine-containing gas to a substrate including an insulating film andhaving the recess, and a step of forming a ruthenium film in the recessby supplying a Ru-containing precursor to the recess to which thechlorine is adsorbed. The details will be described below.

First, as shown in FIG. 1A, a substrate 100 having an insulating film102 formed on a metal layer 101 is prepared. The substrate 100 is, forexample, a semiconductor wafer such as a silicon wafer or the like. Themetal layer 101 is, for example, a wiring material such as a tungstenfilm or the like. The insulating film 102 is, for example, a laminatedfilm of a silicon nitride film 102 a and a silicon oxide film 102 b. Thesilicon nitride film 102 a is, for example, an etching stopper layer.The silicon oxide film 102 b is, for example, an interlayer insulatingfilm. The insulating film 102 may be a single layer film such as asilicon nitride film or a silicon oxide film. A recess 103 such as atrench or a hole is formed in the insulating film 102. The metal layer101 is exposed on a bottom surface 103 c of the recess 103. When anatural oxide film or the like is formed on the exposed surface of themetal layer 101, a cleaning step of removing the natural oxide film orthe like may be performed. The cleaning step is, for example, a step ofremoving the oxide film formed on the bottom surface 103 c of the recess103 (the exposed surface of the metal layer 101) by supplying achlorine-containing gas to the bottom surface 103 c of the recess 103.For example, a tungsten oxide film may be removed by alternatelysupplying a chlorine (Cl₂) gas and plasma using an argon (Ar) gas. Whenthe processing temperature is high (e.g., 200 degrees C. or higher), thetungsten oxide film may be removed by supplying only the Cl₂ gas withoutusing the plasma of the Ar gas. In addition, the tungsten oxide film maybe physically removed by performing sputtering with the plasma of the Argas.

Subsequently, as shown in FIG. 1B, a chlorine-containing gas is suppliedto the substrate 100 so that chlorine 104 is adsorbed to the upperportion of the recess 103 at a higher density than to the lower portionof the recess 103. For example, the chlorine 104 is adsorbed to an uppersurface 103 a and the upper portion of a side surface 103 b of therecess 103. The chlorine 104 is not adsorbed to the lower portion of theside surface 103 b and the bottom surface 103 c of the recess 103. Themethod of causing the chlorine 104 to be adsorbed to the upper portionof the recess 103 at a higher density than to the lower portion of therecess 103 is not particularly limited, and may be, for example, amethod of supplying a chlorine-containing gas into a depressurizedprocessing container by activating the chlorine-containing gas withplasma. Furthermore, the method may be, for example, a method ofadjusting a process condition such as a pressure, a temperature, a gasflow rate, and the like in a processing container without activating achlorine-containing gas with plasma. The chlorine-containing gas is, forexample, a Cl₂ gas.

Subsequently, as shown in FIG. 1C, a ruthenium film 105 is formed in therecess 103 by supplying a Ru-containing precursor to the recess 103 towhich the chlorine 104 is adsorbed. At this time, the chlorine 104serves as an adsorption inhibition layer that inhibits adsorption of theRu-containing precursor. Therefore, the ruthenium film 105 is hard to beformed on the surface of the recess 103 to which the chlorine 104 isadsorbed. For that reason, at the initial stage of film formation, theruthenium film 105 is thickly formed on the lower portion of the sidesurface 103 b and the bottom surface 103 c of the recess 103 to whichthe chlorine 104 is not adsorbed. On the other hand, the ruthenium film105 is scarcely formed on the upper surface 103 a and the upper portionof the side surface 103 b of the recess 103 to which the chlorine 104 isadsorbed, or is formed more thinly on the upper surface 103 a and theupper portion of the side surface 103 b of the recess 103 than on thelower portion of the side surface 103 b and the bottom surface 103 c ofthe recess 103. As a result, the ruthenium film 105 is formed in a Vshape in the recess 103. The Ru-containing precursor is, for example,triruthenium dodecacarbonyl (Ru₃(CO)₁₂), η⁴-2,3-dimethylbutadieneruthenium tricarbonyl (Ru(DMBD)(CO)₃),(2,4-dimethylpentadienylxethylcyclopentadienyl) ruthenium(Ru(DMPD)(EtCp)), bis(2,4-dimethylpentadienyl) ruthenium (Ru(DMPD)₂),4-dimethylpentadienyl (methylcyclopentadienyl) ruthenium(Ru(DMPD)(MeCp), bis (cyclopentadienyl) ruthenium (Ru(C₅H₅)₂),cis-dicarbonyl bis (5-methylhexane-2,4-dionate) ruthenium (II), or thelike.

Subsequently, as shown in FIGS. 1D and 1E, the ruthenium film 105 isembedded in the recess 103 by continuously supplying the Ru-containingprecursor to the recess 103. At this time, since the ruthenium film 105is formed in a V shape in the recess 103 at the initial stage of filmformation, bottom-up film formation is performed in which film formationgradually progresses upward from the bottom surface 103 c of the recess103. As a result, as shown in FIG. 1F, the ruthenium film 105 in whichgeneration of voids, seams, and the like is suppressed can be formed inthe recess 103. That is to say, the ruthenium film 105 having goodembedding characteristics can be formed in the recess 103.

Another example of the ruthenium film forming method according to oneembodiment will be described. FIGS. 2A to 2I are sectional process viewsshowing another example of the ruthenium film forming method accordingto one embodiment.

The ruthenium film forming method shown in FIGS. 2A to 2I is a method offorming a ruthenium film in a recess by alternately repeating the stepof causing the chlorine to be adsorbed and the step of forming theruthenium film, which are adopted in the ruthenium film forming methodshown in FIGS. 1A to 1F. The details will be described below.

First, as shown in FIG. 2A, a substrate 200 having an insulating film202 formed on a metal layer 201 is prepared. The substrate 200 is, forexample, a semiconductor wafer such as a silicon wafer or the like. Themetal layer 201 is, for example, a wiring material such as a tungstenfilm. The insulating film 202 is, for example, a laminated film of asilicon nitride film 202 a and a silicon oxide film 202 b. The siliconnitride film 202 a is, for example, an etching stopper layer. Thesilicon oxide film 202 b is, for example, an interlayer insulating film.The insulating film 202 may be, for example, a single layer film such asa silicon nitride film or a silicon oxide film. A recess 203 such as atrench or a hole is formed in the insulating film 202. The metal layer201 is exposed at a bottom surface 203 c of the recess 203. When anatural oxide film or the like is formed on the exposed surface of themetal layer 201, a cleaning step of removing the natural oxide film orthe like may be performed. The cleaning step is, for example, a step ofsupplying a chlorine-containing gas to the bottom surface 203 c of therecess 203 to remove the oxide film formed on the bottom surface 203 cof the recess 203 (the exposed surface of the metal layer 201). Forexample, a tungsten oxide film may be removed by alternately supplying aCl₂ gas and plasma of an Ar gas. When the processing temperature is high(e.g., 200 degrees C. or higher), the tungsten oxide film may be removedby supplying only the Cl₂ gas without using the plasma of the Ar gas. Inaddition, the tungsten oxide film may be physically removed byperforming sputtering with the plasma of the Ar gas.

Subsequently, as shown in FIG. 2B, a chlorine-containing gas is suppliedto the substrate 200 so that chlorine 204 is adsorbed to the upperportion of the recess 203 at a higher density than to the lower portionof the recess 203. For example, the chlorine 204 is adsorbed to an uppersurface 203 a and the upper portion of a side surface 203 b of therecess 203, and the chlorine 204 is not adsorbed to the lower portion ofthe side surface 203 b and the bottom surface 203 c of the recess 203.The method of causing the chlorine 204 to be adsorbed to the upperportion of the recess 103 at a higher density than to the lower portionof the recess 203 is not particularly limited, and may be, for example,a method of supplying a chlorine-containing gas into a depressurizedprocessing container by activating the chlorine-containing gas withplasma. Furthermore, the method may be, for example, a method ofadjusting a process condition such as a pressure, a temperature, a gasflow rate, and the like in a processing container without activating achlorine-containing gas with plasma. The chlorine-containing gas is, forexample, a Cl₂ gas.

Subsequently, as shown in FIG. 2C, a ruthenium film 205 is formed in therecess 203 by supplying a Ru-containing precursor to the recess 203 towhich the chlorine 204 is adsorbed. At this time, the chlorine 204serves as an adsorption inhibition layer that inhibits adsorption of theRu-containing precursor. Therefore, it is hard for the ruthenium film205 to be formed on the surface of the recess 203 to which the chlorine104 is adsorbed. For that reason, at the initial stage of filmformation, the ruthenium film 205 is thickly formed on the lower portionof the side surface 203 b and the bottom surface 203 c of the recess 203to which the chlorine 204 is not adsorbed. On the other hand, theruthenium film 205 is scarcely formed on the upper surface 203 a and theupper portion of the side surface 203 b of the recess 203 to which thechlorine 204 is adsorbed, or is formed more thinly on the upper surface203 a and the upper portion of the side surface 203 b of the recess 203than on the lower portion of the side surface 203 b and the bottomsurface 203 c of the recess 203. As a result, the ruthenium film 205 isformed in a V shape in the recess 203. The Ru-containing precursor maybe, for example, the same as the Ru-containing precursor used in theruthenium film forming method shown in FIGS. 1A to 1F described above.

Subsequently, as shown in FIG. 2D, a chlorine-containing gas is suppliedto the substrate 200 so that chlorine 204 is adsorbed to the upperportion of the recess 203 at a higher density than to the lower portionof the recess 203. For example, the chlorine 204 is adsorbed to theupper surface 203 a and the upper portion of the side surface 203 b ofthe recess 203, and the chlorine 204 is not adsorbed to the lowerportion of the side surface 203 b and the bottom surface 203 c of therecess 203. The method of causing the chlorine 204 to be adsorbed to theupper portion of the recess 103 at a higher density than to the lowerportion of the recess 203 is not particularly limited, and may be, forexample, a method of supplying a chlorine-containing gas into adepressurized processing container by activating the chlorine-containinggas with plasma. Furthermore, the method may be, for example, a methodof adjusting a process condition such as a pressure, a temperature, agas flow rate, and the like in a processing container without activatinga chlorine-containing gas with plasma. The chlorine-containing gas is,for example, a Cl₂ gas.

Subsequently, as shown in FIG. 2E, a ruthenium film 205 is formed in therecess 203 by supplying a Ru-containing precursor to the recess 203 towhich the chlorine 204 is adsorbed. At this time, the chlorine 204serves as an adsorption inhibition layer that inhibits adsorption of theRu-containing precursor. Therefore, it is hard for the ruthenium film205 to be formed on the surface of the recess 203 to which the chlorine104 is adsorbed. For that reason, a ruthenium film 205 is thickly formedon the surface of the ruthenium film 205 formed on the lower portion ofthe side surface 203 b and the bottom surface 203 c of the recess 203 towhich the chlorine 204 is not adsorbed. On the other hand, the rutheniumfilm 205 is scarcely formed on the upper surface 203 a and the upperportion of the side surface 203 b of the recess 203 to which thechlorine 204 is adsorbed, or is formed more thinly on the upper surface203 a and the upper portion of the side surface 203 b of the recess 203than on the surface of the ruthenium film 205 formed on the lowerportion of the side surface 203 b and the bottom surface 203 c of therecess 203. As a result, the ruthenium film 205 is formed in a V shapein the recess 203. The Ru-containing precursor may be, for example, thesame as the Ru-containing precursor used in the ruthenium film formingmethod shown in FIGS. 1A to 1F described above.

Subsequently, as shown in FIGS. 2F to 2I, the adsorption of the chlorine204 and the formation of the ruthenium film 205 are alternately repeatedto embed the ruthenium film 205 in the recess 203. At this time, sincethe ruthenium film 205 is embedded in the recess 203 by alternatelyrepeating the adsorption of the chlorine and the formation of theruthenium film 205, the bottom-up film formation in which film formationgradually progresses upward from the bottom surface 203 c of the recess203 is promoted. As a result, even when the recess 203 has a high aspectratio (ratio of the depth to the opening width of the recess 203), it ispossible to form the ruthenium film 205 in which generation of voids,seams and the like is suppressed. That is, the ruthenium film 205 havinggood embedding characteristics can be formed in the recess 203 having ahigh aspect ratio.

[Substrate Processing System]

An example of a substrate processing system that realizes the rutheniumfilm forming method according to one embodiment will be described. FIG.3 is a schematic diagram showing a configuration example of thesubstrate processing system.

A substrate processing system 1 includes processing chambers 11 to 14, avacuum transfer chamber 20, load lock chambers 31 and 32, an atmospherictransfer chamber 40, load ports 51 to 53, gate valves 61 to 68, and acontrol device 70.

The processing chamber 11 includes a stage 11 a on which a semiconductorwafer (hereinafter referred to as “wafer W”) is mounted, and isconnected to the vacuum transfer chamber 20 via the gate valve 61.Similarly, the processing chamber 12 includes a stage 12 a on which thewafer W is mounted, and is connected to the vacuum transfer chamber 20via the gate valve 62. The processing chamber 13 includes a stage 13 aon which the wafer W is mounted, and is connected to the vacuum transferchamber 20 via the gate valve 63. The processing chamber 14 includes astage 14 a on which the wafer W is mounted, and is connected to thevacuum transfer chamber 20 via the gate valve 64. The interiors of theprocessing chambers 11 to 14 are depressurized to a predetermined vacuumatmosphere, and the wafer W is subjected to desired processes (anetching process, a film-forming process, a cleaning process, an ashingprocess, and the like) inside the processing chambers 11 to 14.Operations of the respective components for performing processes in theprocessing chambers 11 to 14 are controlled by the control device 70.

The interior of the vacuum transfer chamber 20 is depressurized to apredetermined vacuum atmosphere. A transfer mechanism 21 is provided inthe vacuum transfer chamber 20. The transfer mechanism 21 transfers thewafer W to and from the processing chambers 11 to 14 and the load lockchambers 31 and 32. Operation of the transfer mechanism 21 is controlledby the control device 70.

The load lock chamber 31 includes a stage 31 a on which the wafer W ismounted. The load lock chamber 31 is connected to the vacuum transferchamber 20 via the gate valve 65 and is connected to the atmospheretransfer chamber 40 via the gate valve 67. Similarly, the load lockchamber 32 includes a stage 32 a on which the wafer W is mounted. Theload lock chamber 32 is connected to the vacuum transfer chamber 20 viathe gate valve 66 and is connected to the atmosphere transfer chamber 40via the gate valve 68. The interiors of the load lock chambers 31 and 32may be switched between atmospheric atmosphere and a vacuum atmosphere.The control device 70 controls the switching between the vacuumatmosphere and atmospheric atmosphere in the load lock chambers 31 and32.

The interior of the atmosphere transfer chamber 40 is kept inatmospheric atmosphere. For example, a down-flow of a clean air isformed inside the atmosphere transfer chamber 40. A transfer mechanism41 is provided in the atmosphere transfer chamber 40. The transfermechanism 41 transfers the wafer W to and from the load lock chambers 31and 32 and carriers C in the load ports 51 to 53. Operation of thetransfer mechanism 41 is controlled by the control device 70.

The load ports 51 to 53 are provided on a long side wall surface of theatmosphere transfer chamber 40. A carrier C containing wafers W or anempty carrier C is attached to the load ports 51 to 53. The carrier Cis, for example, a front opening unified pod (FOUP).

The gate valves 61 to 68 are configured to be openable and closable. Theopening and closing of the gate valves 61 to 68 are controlled by thecontrol device 70.

The control device 70 controls the substrate processing system 1 as awhole by performing the operations of the processing chambers 11 to 14,the operations of the transfer mechanisms 21 and 41, the opening andclosing of the gate valves 61 to 68, and the switching of the vacuumatmosphere and atmospheric atmosphere in the load lock chambers 31 and32.

Next, an example of operation of the substrate processing system will bedescribed. For example, the control device 70 opens the gate valve 67and controls the transfer mechanism 41 to transfer, for example, thewafer W accommodated in the carrier C of the load port 51 to the stage31 a of the load lock chamber 31. The control device 70 closes the gatevalve 67 and keeps the interior of the load lock chamber 31 in a vacuumatmosphere.

The control device 70 opens the gate valves 61 and 65 and controls thetransfer mechanism 21 to transfer the wafer W in the load lock chamber31 to the stage 11 a of the processing chamber 11. The control device 70closes the gate valves 61 and 65 and operates the processing chamber 11.As a result, the wafer W is subjected to a predetermined process (e.g.,the aforementioned process of the step of causing chlorine to beadsorbed) in the processing chamber 11.

Subsequently, the control device 70 opens the gate valves 61 and 63 andcontrols the transfer mechanism 21 to transfer the wafer W processed inthe processing chamber 11 to the stage 13 a of the processing chamber13. The control device 70 closes the gate valves 61 and 63 and operatesthe processing chamber 13. As a result, the wafer W is subjected to apredetermined process (e.g., the aforementioned process of the step offorming a ruthenium film) in the processing chamber 13.

The control device 70 may transfer the wafer W processed in theprocessing chamber 11 to the stage 14 a of the processing chamber 14capable of performing the same process as in the processing chamber 13.In one embodiment, the wafer W in the processing chamber 11 istransferred to the processing chamber 13 or the processing chamber 14depending on the operating states of the processing chamber 13 and theprocessing chamber 14. As a result, the control device 70 may use theprocessing chamber 13 and the processing chamber 14 to perform apredetermined process (e.g., the aforementioned process of the step offorming a ruthenium film) on a plurality of wafers W in parallel. Thismakes it possible to enhance the productivity.

The control device 70 controls the transfer mechanism 21 to transfer thewafer W processed in the processing chamber 13 or the processing chamber14 to the stage 31 a of the load lock chamber 31 or the stage 32 a ofthe load lock chamber 32. The control device 70 keeps the interior ofthe load lock chamber 31 or the load lock chamber 32 in atmosphericatmosphere. The control device 70 opens the gate valve 67 or the gatevalve 68 and controls the transfer mechanism 41 to transfer the wafer Win the load lock chamber 32 to, for example, the carrier C in the loadport 53 and store the wafer W in the carrier C.

As described above, according to the substrate processing system 1 shownin FIG. 3 , while the wafer W is processed by each processing chamber,the wafer W can be subjected to a predetermined process without exposingthe wafer W to the atmosphere, i.e., without breaking the vacuum.

[Processing Apparatus]

A configuration example of a processing apparatus 400 that realizes theprocessing chamber used for the process of the step of causing thechlorine to be adsorbed in the ruthenium film forming method accordingto one embodiment will be described. FIG. 4 is a schematic diagramshowing an example of the processing apparatus 400 that executes theprocess of the step of causing the chlorine to be adsorbed.

The processing apparatus 400 shown in FIG. 4 is, for example, anapparatus that performs a step of causing chlorine to be adsorbed. Inthe processing apparatus 400, for example, a chlorine-containing gas issupplied to perform a process of causing chlorine to be adsorbed to thewafer W. Hereinafter, the processing apparatus 400 used in theprocessing chamber 11 will be described by way of example.

The processing apparatus 400 includes a processing container 410, astage 420, a shower head 430, an exhauster 440, a gas supply mechanism450, and a control device 460.

The processing container 410 is made of metal such as aluminum or thelike and has a substantially cylindrical shape.

A loading and unloading port 411 for loading and unloading the wafer Wis formed on a sidewall of the processing container 410. The loading andunloading port 411 is opened or closed by agate valve 412. An annularexhaust duct 413 having a rectangular cross section is provided on amain body of the processing container 410. A slit 413 a is formed in theexhaust duct 413 along the inner circumferential surface thereof. Anexhaust port 413 b is formed on the outer wall of the exhaust duct 413.A ceiling wall 414 is provided on the upper surface of the exhaust duct413 so as to close the upper opening of the processing container 410. Agap between the exhaust duct 413 and the ceiling wall 414 ishermetically sealed by a seal ring 415.

The stage 420 is a member that horizontally supports the wafer W in theprocessing container 410, and is illustrated as the stage 11 a in FIG. 3. The stage 420 is formed in a disk shape having a size corresponding tothe wafer W and is supported by a support 423. The stage 420 is made ofceramic material such as aluminum nitride (AlN) or the like, or ametallic material such as aluminum, nickel alloy, or the like. A heater421 for heating the wafer W and an electrode 429 are embedded in thestage 420. The heater 421 is supplied with an electric power from aheater power source (not shown) to generate heat. The output of theheater 421 is controlled by a temperature signal of a thermocouple (notshown) provided near the upper surface of the stage 420, whereby thewafer W is controlled to a predetermined temperature.

A first high frequency power source 444 is connected to the electrode429 via a matcher 443. The matcher 443 matches a load impedance with aninternal impedance of the first high frequency power source 444. Thefirst high frequency power source 444 applies an electric power of apredetermined frequency to the stage 420 via the electrode 429. Forexample, the first high frequency power source 444 applies highfrequency power of 13.56 MHz to the stage 420 via the electrode 429. Thehigh frequency power is not limited to 13.56 MHz. For example, highfrequency power of 450 KHz, 2 MHz, 27 MHz, 60 MHz, 100 MHz, or the likemay be appropriately used. In this way, the stage 420 also functions asa lower electrode.

Furthermore, the electrode 429 is connected to an adsorption powersource 449 via an ON/OFF switch 448 arranged outside the processingcontainer 410, and also functions as an electrode for attracting thewafer W toward the stage 420.

Furthermore, the shower head 430 is connected to a second high frequencypower source 446 via a matcher 445. The matcher 445 matches a loadimpedance with an internal impedance of the second high frequency powersource 446. The second high frequency power source 446 applies anelectric power of a predetermined frequency to the shower head 430. Forexample, the second high frequency power supply 446 applies highfrequency power of 13.56 MHz to the shower head 430. The high frequencypower is not limited to 13.56 MHz. For example, high frequency power of450 KHz. 2 MHz, 27 MHz, 60 MHz, 100 MHz, or the like may beappropriately used. In this way, the shower head 430 also functions asan upper electrode.

In the stage 420, a cover member 422 made of ceramics such as alumina orthe like is provided so as to cover the outer peripheral region of theupper surface and the side surface of the stage 420. An adjustmentmechanism 447 that adjusts a gap G between the upper electrode and thelower electrode is provided on the bottom surface of the stage 420. Theadjustment mechanism 447 includes the support 423 and an elevatingmechanism 424. The support 423 supports the stage 420 at the center ofthe bottom surface of the stage 420. In addition, the support 423extends through a hole formed in the bottom wall of the processingcontainer 410 and extends to below the processing container 410. Thelower end of the support 423 is connected to the elevating mechanism424. The stage 420 is moved up and down by the elevating mechanism 424via the support 423. The adjustment mechanism 447 may move the elevatingmechanism 424 up and down between a processing position indicated by asolid line in FIG. 4 and a delivery position located below theprocessing position as indicated by a two-dot chain line so that thewafer W can be transferred. This makes it possible to load and unloadthe wafer W.

A flange 425 is attached to the support 423 below the processingcontainer 410. A bellows 426 that separates the atmosphere in theprocessing container 410 from the ambient air and expands and contractsas the stage 420 moves up and down is provided between the bottomsurface of the processing container 410 and the flange 425.

In the vicinity of the bottom surface of the processing container 410,three lift pins 427 (only two of which are shown) are provided so as toprotrude upward from a lift plate 427 a. The lift pins 427 are raisedand lowered via the lift plate 427 a by a lift mechanism 428 providedbelow the processing container 410.

The lift pins 427 are inserted into through-holes 420 a provided in thestage 420 located at the delivery position and can protrude or retractwith respect to the upper surface of the stage 420. By raising andlowering the lift pins 427, the wafer W is delivered between thetransfer mechanism (not shown) and the stage 420.

The shower head 430 supplies a process gas into the processing container410 in a shower shape. The shower head 430 is made of metal and isprovided so as to face the stage 420. The shower head 430 has a diametersubstantially equal to that of the stage 420. The shower head 430includes a main body 431 fixed to the ceiling wall 414 of the processingcontainer 410, and a shower plate 432 connected to the underside of themain body 431. A gas diffusion space 433 is formed between the main body431 and the shower plate 432, and a gas introduction hole 436 loading tothe gas diffusion space 433 is provided so as to pass through theceiling wall 414 of the processing container 410 and the center of themain body 431. An annular protrusion 434 that protrudes downward isformed at the peripheral edge portion of the shower plate 432. Gasdischarge holes 435 are formed on the inner flat surface of the annularprotrusion 434. When the stage 420 is in the processing position, aprocessing space 438 is formed between the stage 420 and the showerplate 432, and the upper surface of the cover member 422 comes close tothe annular protrusion 434 to form an annular gap 439.

The exhauster 440 evacuates the interior of the processing container410. The exhauster 440 includes an exhaust pipe 441 connected to theexhaust port 413 b, and an exhaust mechanism 442 connected to theexhaust pipe 441 and provided with a vacuum pump, a pressure controlvalve, and the like. At the time of processing, the gas in theprocessing container 410 is moved to the exhaust duct 413 through theslit 413 a and is exhausted from the exhaust duct 413 through theexhaust pipe 441 by the exhaust mechanism 442.

The gas supply mechanism 450 is connected to the gas introduction hole436 of the shower head 430 via a gas supply line 437. The gas supplymechanism 450 is connected to gas supply sources of various gases usedin the process of the step of causing the chlorine to be adsorbed,through gas supply lines, respectively. For example, the gas supplymechanism 450 is connected to gas supply sources for supplying variousgases such as a Cl₂ gas, an H₂ gas, a rare gas, and the like, via gassupply lines, respectively.

Each gas supply line is appropriately branched according to the processof the step of causing the chlorine to be adsorbed. An opening andclosing valve and a flow rate controller are provided on each gas supplyline. The gas supply mechanism 450 is capable of controlling the flowrates of various gases by controlling the opening and closing valve andthe flow rate controller provided in each gas supply line. The gassupply mechanism 450 supplies each of various gases including a Cl₂ gasinto the processing container 410 via the gas supply line 437 and theshower head 430 during the process of the step of causing the chlorineto be adsorbed.

Operation of the processing apparatus 400 configured as described aboveis generally controlled by the control device 460. The control device460 is, for example, a computer, and includes a central processing unit(CPU), a random access memory (RAM), a read only memory (ROM), anauxiliary memory device, and the like. The CPU operates based on aprogram stored in the ROM or the auxiliary memory device or a processcondition of the process of the step of causing the chlorine to beadsorbed, and controls the operation of the apparatus as a whole. Forexample, the control device 460 controls the supply operation of variousgases from the gas supply mechanism 450, the elevating operation of theelevating mechanism 424, the evacuating operation of the interior of theprocessing container 410 by the exhaust mechanism 442, and the electricpowers supplied from the first high frequency power source 444 and thesecond high frequency power source 446. The computer-readable programnecessary for control may be stored in a storage medium. The storagemedium is, for example, a flexible disk, a compact disc (CD), a CD-ROM,a hard disk, a flash memory, a DVD, or the like. The control device 460may be provided independently of the control device 70 (see FIG. 3 ), orthe control device 70 may also serve as the control device 460.

An example of the operation of the processing apparatus 400 will bedescribed. At the time of startup, the interior of the processingchamber 11 is kept in a vacuum atmosphere by the exhauster 440. Inaddition, the stage 420 is moved to the delivery position.

The control device 460 opens the gate valve 412. At this time, the waferW is placed on the lift pins 427 by the external transfer mechanism 21.When the transfer mechanism 21 comes out of the loading and unloadingport 411, the control device 460 closes the gate valve 412.

The control device 460 controls the elevating mechanism 424 to move thestage 420 to the processing position. At this time, as the stage 420moves up, the wafer W placed on the lift pins 427 is mounted on themounting surface of the stage 420.

At the processing position, the control device 460 operates the heater421 and turns on the ON/OFF switch 448 to attract the wafer W to thestage 420. Furthermore, the control device 460 controls the gas supplymechanism 450 to supply a process gas such as a chlorine-containing gasor the like, or a carrier gas, into the processing chamber 11 from theshower head 430. As a result, a predetermined process such as theprocess of the step of causing the chlorine to be adsorbed to the waferW is performed. The gas remaining after the process passes through aflow path on the upper surface side of the cover member 422 and isexhausted by the exhaust mechanism 442 via the exhaust pipe 441.

At this time, the control device 460 controls the first high frequencypower source 444 and the matcher 443 to apply an electric power of apredetermined frequency to the stage 420. Furthermore, the controldevice 460 controls the second high frequency power source 446 and thematcher 445 to apply an electric power of a predetermined frequency tothe shower head 430.

When the predetermined process is completed, the control device 460turns off the ON/OFF switch 448 to release the attraction of the wafer Wto the stage 420, and controls the elevating mechanism 424 to move thestage 420 to the delivery position. At this time, head portions of thelift pins 427 protrude from the mounting surface of the stage 420 tolift the wafer W from the mounting surface of the stage 420.

The control device 460 opens the gate valve 412. At this time, the waferW placed on the lift pins 427 is unloaded by the external transfermechanism 21. When the transfer mechanism 21 comes out of the loadingand unloading port 411, the control device 460 closes the gate valve412.

As described above, according to the processing apparatus 400 shown inFIG. 4 , it is possible to perform a predetermined process such as theprocess of the step of causing the chlorine to be adsorbed to the waferW.

A suitable process condition of the step of causing the chlorine to beadsorbed, which is performed using the processing apparatus 400, is asfollows.

Chlorine-containing gas: Cl₂ gas (10 to 1000 sccm)

Pressure in the processing container 410: 1 to 100 mTorr (0.13 to 13 Pa)

Wafer temperature: 60 to 300 degrees C.

Electric power of the second high frequency power source 446: 50 to 500W

Next, a configuration example of a processing apparatus 500 thatrealizes the processing chamber used in the process of the step offorming the ruthenium film in the ruthenium film forming methodaccording to one embodiment will be described. FIG. 5 is a schematicdiagram showing an example of the processing apparatus 500 that performsthe process of the step of forming the ruthenium film.

The processing apparatus 500 shown in FIG. 5 is a chemical vapordeposition (CVD) apparatus and is, for example, an apparatus forperforming the step of forming the ruthenium film. In the processingapparatus 500, for example, a ruthenium-containing precursor is suppliedto perform the step of forming the ruthenium film on the wafer W.Hereinafter, the processing apparatus 500 used in the processing chamber13 will be described by way of example.

A main body container 501 is a bottom-closed container having an openingon the upper side thereof. A support 502 supports a gas dischargemechanism 503. Furthermore, the support 502 closes the upper opening ofthe main body container 501 so that the main body container 501 ishermetically sealed to form the processing chamber 13 (also see FIG. 3). A gas supplier 504 supplies a process gas such as aruthenium-containing gas or the like, or a carrier gas, to the gasdischarge mechanism 503 via a supply pipe 502 a penetrating the support502. The ruthenium-containing gas or the carrier gas supplied from thegas supplier 504 is supplied from the gas discharge mechanism 503 intothe processing chamber 13.

A stage 505 is a member on which the wafer W is mounted, and isillustrated as the stage 13 a in FIG. 3 . Inside the stage 505, a heater506 for heating the wafer W is provided. Furthermore, the stage 505includes a support 505 a which extends downward from the center of thelower surface of the stage 505 and which has one end penetrating thebottom portion of the main body container 501 and supported by anelevating mechanism via an elevating plate 509. Furthermore, the stage505 is fixed on a temperature control jacket 508, which is a temperaturecontrol member, via a heat insulating ring 507. The temperature controljacket 508 includes a plate portion for fixing the stage 505, a shaftportion extending downward from the plate portion and configured tocover the support 505 a, and a hole portion extending through the shaftportion from the plate portion.

The shaft portion of the temperature control jacket 508 penetrates thebottom portion of the main body container 501. The lower end portion ofthe temperature control jacket 508 is supported by an elevatingmechanism 510 via the elevating plate 509 arranged below the main bodycontainer 501. A bellows 511 is provided between the bottom portion ofthe main body container 501 and the elevating plate 509. Theairtightness inside the main body container 501 is maintained even whenthe elevating plate 509 moves up and down.

When the elevating mechanism 510 raises and lowers the elevating plate509, the stage 505 moves up and down between a processing position (seeFIG. 5 ) where the wafer W is processed and a delivery position (notshown) where the wafer W is delivered to and from the external transfermechanism 21 (see FIG. 3 ) via a loading and unloading port 501 a.

Lift pins 512 support the lower surface of the wafer W and lift thewafer W from the mounting surface of the stage 505 when the wafer W isdelivered to and from the external transfer mechanism 21 (see FIG. 3 ).Each of the lift pins 512 includes a shaft portion and a head portionhaving a diameter larger than that of the shaft portion. Through-holesthrough which the shaft portions of the lift pins 512 are inserted areformed in the stage 505 and the plate portion of the temperature controljacket 508. In addition, groove portions for accommodating the headportions of the lift pins 512 are formed on the mounting surface side ofthe stage 505. A contact member 513 is arranged below the lift pins 512.

In a state in which the stage 505 moved to the processing position forthe wafer W (see FIG. 5 ), the head portions of the lift pins 512 areaccommodated in the groove portions, and the wafer W is mounted on themounting surface of the stage 505. Furthermore, the head portions of thelift pins 512 are locked in the groove portions, the shaft portions ofthe lift pins 512 penetrate the stage 505 and the plate portion of thetemperature control jacket 508, and the lower ends of the shaft portionsof the lift pins 512 protrude from the plate portion of the temperaturecontrol jacket 508. On the other hand, in a state where the stage 505 ismoved to the delivery position (not shown) for the wafer W, the lowerends of the lift pins 512 make contact with the contact member 513, andthe head portions of the lift pins 512 protrude from the mountingsurface of the stage 505. As a result, the head portions of the liftpins 512 support the lower surface of the wafer W and lift the wafer Wfrom the mounting surface of the stage 505.

An annular member 514 is arranged above the stage 505. In a state inwhich the stage 505 is moved to the processing position for the wafer W(see FIG. 5 ), the annular member 514 makes contact with the outerperipheral portion of the upper surface of the wafer W, and the weightof the annular member 514 causes the wafer W to be pressed against themounting surface of the stage 505. On the other hand, in a state inwhich the stage 505 is moved to the delivery position (not shown) forthe wafer W, the annular member 514 is locked by a locking part (notshown) at a position above the loading and unloading port 501 a. As aresult, the delivery of the wafer W by the transfer mechanism 21 (seeFIG. 3 ) is not hindered.

A chiller unit 515 circulates a coolant, for example, cooling water,through a flow path 508 a formed in the plate portion of the temperaturecontrol jacket 508 via pipes 515 a and 515 b.

A heat transfer gas supplier 516 supplies a heat transfer gas such as anHe gas or the like to between the back surface of the wafer W mounted onthe stage 505 and the mounting surface of the stage 505 via a pipe 516a.

A purge gas supplier 517 supplies a purge gas to a pipe 517 a, a gapbetween the support 505 a and the hole portion of the temperaturecontrol jacket 508, a flow path formed between the stage 505 and theheat insulating ring 507 to extend radially outward, and a vertical flowpath formed in the outer peripheral portion of the stage 505. The purgegas such as, for example, a carbon monoxide (CO) gas or the like issupplied to between the lower surface of the annular member 514 and theupper surface of the stage 505 through these flow paths. This preventsthe process gas from flowing into a space between the lower surface ofthe annular member 514 and the upper surface of the stage 505, therebypreventing film formation on the lower surface of the annular member 514or on the upper surface of the outer peripheral portion of the stage505.

On the side wall of the main body container 501, the loading andunloading port 501 a for loading and unloading the wafer W and a gatevalve 518 for opening and closing the loading and unloading port 501 aare provided. The gate valve 518 is shown as the gate valve 63 in FIG. 3.

An exhauster 519 including a vacuum pump and the like is connected tothe lower side wall of the main body container 501 via an exhaust pipe501 b. The interior of the main body container 501 is evacuated by theexhauster 519, and the interior of the processing chamber 13 is set toand maintained in a predetermined vacuum atmosphere (e.g., 1.33 Pa).

A control device 520 controls the gas supplier 504, the heater 506, theelevating mechanism 510, the chiller unit 515, the heat transfer gassupplier 516, the purge gas supplier 517, the gate valve 518, theexhauster 519, and the like, thereby controlling the operation of theprocessing apparatus 500. The control device 520 may be providedindependently of the control device 70 (see FIG. 3 ). The control device70 may also serve as the control device 520.

An example of operation of the processing apparatus 500 will bedescribed. At the time of startup, the interior of the processingchamber 13 is kept in a vacuum atmosphere by the exhauster 519. Thestage 505 is moved to the delivery position.

The control device 520 opens the gate valve 518. At this time, the waferW is placed on the lift pins 512 by the external transfer mechanism 21.When the transfer mechanism 21 comes out of the loading and unloadingport 501 a, the control device 520 closes the gate valve 518.

The control device 520 controls the elevating mechanism 510 to move thestage 505 to the processing position. At this time, as the stage 505moves up, the wafer W placed on the lift pins 512 is mounted on themounting surface of the stage 505. Furthermore, the annular member 514makes contact with the outer peripheral portion of the upper surface ofthe wafer W. and the weight of the annular member 514 causes the wafer Wto be pressed against the mounting surface of the stage 505.

At the processing position, the control device 520 operates the heater506 and controls the gas supplier 504 to supply a process gas such as aruthenium-containing gas or the like, or a carrier gas, from the gasdischarge mechanism 503 into the processing chamber 12. As a result, apredetermined process such as the process of the step of forming theruthenium film on the wafer W is performed. The gas remaining after theprocess passes through a flow path on the upper surface side of theannular member 514 and is exhausted by the exhauster 519 via the exhaustpipe 501 b.

At this time, the control device 520 controls the heat transfer gassupplier 516 to supply a heat transfer gas between the back surface ofthe wafer W mounted on the stage 505 and the mounting surface of thestage 505. Furthermore, the control device 520 controls the purge gassupplier 517 to supply a purge gas to between the lower surface of theannular member 514 and the upper surface of the stage 505. The purge gaspasses through a flow path on the lower surface side of the annularmember 514 and is exhausted by the exhauster 519 via the exhaust pipe501 b.

When the predetermined process is completed, the control device 520controls the elevating mechanism 510 to move the stage 505 to thedelivery position. At this time, as the stage 505 moves down, theannular member 514 is locked by the locking portion (not shown).Furthermore, when the lower ends of the lift pins 512 makes contact withthe contact member 513, the head portions of the lift pins 512 protrudefrom the mounting surface of the stage 505 and lift the wafer W from themounting surface of the stage 505.

The control device 520 opens the gate valve 518. At this time, the waferW placed on the lift pins 512 is unloaded by the external transfermechanism 21. When the transfer mechanism 21 comes out of the loadingand unloading port 501 a, the control device 520 closes the gate valve518.

As described above, according to the processing apparatus 500 shown inFIG. 5 , it is possible to perform a predetermined process such as theprocess of the step of forming the ruthenium film on the wafer W.

Although the processing apparatus 400 having the processing chamber 11and the processing apparatus 500 having the processing chamber 13 havebeen described above, a processing apparatus having the processingchamber 12 and a processing apparatus having the processing chamber 14may have the same configuration as that of any one of theabove-described processing apparatuses, or may have a differentconfiguration from that of any one of the above-described processingapparatuses. The configuration of the processing apparatus isappropriately applicable from the viewpoint of the operating rate or theproductivity.

Example

Next, an example conducted to verify the adsorption inhibition effect ofchlorine against the Ru-containing precursor will be described.

In the example, first, two wafers were prepared in which a TiN film 602and a tungsten film 603 are stacked in the named order on a silicon base601.

Subsequently, one of the prepared wafers was subjected to a process of astep of causing chlorine to be adsorbed in the processing chamber 11,and then subjected to a process of a step of forming a ruthenium film604 in the processing chamber 13. Furthermore, the other of the preparedwafers was subjected to a process of a step of forming a ruthenium film604 in the processing chamber 13 without being subjected to a process ofa step of causing chlorine to be adsorbed in the processing chamber 11.The process conditions of the process of the step of forming theruthenium film 604, which is performed in the processing chamber 13 onthe one wafer and the other wafer, are the same. The process conditionsof the step of causing the chlorine to be adsorbed and the step offorming the ruthenium film 604 are as follows.

(Step of Causing the Chlorine to be Adsorbed)

Chlorine-containing gas: Cl₂ gas (240 sccm)

Processing pressure: 30 mTorr (4 Pa)

Wafer temperature: 60 degrees C.

(Step of Forming the Ruthenium Film 604)

Processing pressure: 20 mTorr (2.7 Pa)

Wafer temperature: 155 degrees C.

Then, the film thickness of the ruthenium film 604 formed on thetungsten film 603 was evaluated by observing the cross sections of thetwo wafers using a transmission electron microscope (TEM).

FIGS. 6A and 6B are views for explaining an adsorption inhibition effectof chlorine and are TEM images of the cross section of the rutheniumfilm 604 formed on the tungsten film 603.

FIG. 6A shows the cross section of the wafer that has been subjected tothe process of the step of causing the chlorine to be adsorbed in theprocessing chamber 11 and then subjected to the process of the step offorming the ruthenium film 604 in the processing chamber 13. FIG. 6Bshows the cross section of the wafer that has been subjected to theprocess of the step of forming the ruthenium film 604 in the processingchamber 13 without being subjected to the process of the step of causingthe chlorine to be adsorbed in the processing chamber 11.

As shown in FIGS. 6A and 6B, it can be noted that a film thickness T1 ofthe ruthenium film 604 (see FIG. 6A) when the process of the step ofcausing the chlorine to be adsorbed was performed in the processingchamber 11 is equal to or less than one half of a film thickness T2 ofthe ruthenium film 604 (see FIG. 6B) when the process of the step ofcausing the chlorine to be adsorbed was not performed in the processingchamber 11. From this result, it can be said that the chlorine adsorbedto the tungsten film 603 has an action of inhibiting the adsorption ofthe Ru-containing precursor.

In the above embodiment, there has been described the case where thestep of causing the chlorine to be adsorbed and the step of forming theruthenium film are performed in different processing containersconnected via the vacuum transfer chamber. However, the presentdisclosure is not limited thereto. For example, the step of causing thechlorine to be adsorbed and the step of forming the ruthenium film maybe performed in the same processing container. However, when theprocessing temperature differs between the step of causing the chlorineto be adsorbed and the step of forming the ruthenium film, it ispreferable from the viewpoint of productivity that the step of causingthe chlorine to be adsorbed and the step of forming the ruthenium filmare performed in different processing containers.

According to the present disclosure in some embodiments, it is possibleto form a ruthenium film with good embedding characteristics.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosures.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

What is claimed is:
 1. A substrate processing system, comprising: avacuum transfer chamber having a transfer mechanism configured totransfer a substrate in a depressurized state; a first processingapparatus connected to the vacuum transfer chamber; a second processingapparatus connected to the vacuum transfer chamber; and a controller,wherein the controller is programmed to control the vacuum transferchamber, the first processing apparatus, and the second processingapparatus so as to sequentially execute: transferring the substrateincluding an insulating film and having a recess to the first processingapparatus; forming an inhibition layer in the recess by supplying achlorine-containing gas to the substrate in a depressurized state in thefirst processing apparatus; transferring the substrate from the firstprocessing apparatus to the second processing apparatus via the vacuumtransfer chamber; and forming a ruthenium film in the recess bysupplying a Ru-containing precursor in the second processing apparatusto the recess in which the inhibition layer is formed in thedepressurized state, wherein the controller is further programmed tocause, in the act of forming the inhibition layer, chlorine to beadsorbed to a top surface and an upper portion of a side surface of therecess without adsorbing chlorine to a bottom surface and a lowerportion of the side surface of the recess, so that in the act of formingthe ruthenium film, the chlorine adsorbed to the recess inhibitsadsorption of the Ru-containing precursor to the recess, and wherein thecontroller is further programmed to execute the forming the inhibitionlayer and the forming the ruthenium film alternately and repeatedly toperform bottom-up formation in which film formation gradually progressesupward from the bottom surface of the recess.
 2. The substrateprocessing system of claim 1, wherein the controller is furtherprogrammed to execute, in the forming the inhibition layer, supplyingthe chlorine-containing gas by activating the chlorine-containing gaswith plasma.
 3. The substrate processing system of claim 1, wherein thecontroller is further programmed to execute removing an oxide filmformed on a bottom surface of the recess by supplying thechlorine-containing gas to the recess before the act of forming theinhibition layer.
 4. The substrate processing system of claim 1, whereinthe chlorine-containing gas is a Cl₂ gas, and the Ru-containingprecursor is Ru₃(CO)₁₂.